With the ring back tone service, the user can subscribe the ring back tone for himself, i.e. when the calling party dials the called party, after the ringing and before the called party picks up the phone, the calling party will hear the ring back tone subscribed by the calling party, the called party or the group user. If the ring back tone is subscribed by the calling party, it is the calling party ring back tone; if the ring back tone is subscribed by the called party, it is the called party ring back tone; and if the ring back tone is subscribed by the group user, it is the group user ring back tone. The ring back tone service makes the network ability of the operator available to the end user and provides service support for the user to show his individuality. This service meets the strong requirement of the modern people to show individualities and therefore has obtained a good market feedback.
As one of the voice indications, the ring back tone can only provide the user with the preset indication, which is stored in the operator's server. In addition, no matter the ring back tone in the form of the audio or in the form of the video, they are both transmitted in the call media channel; however, if the calling party uses a multi-path terminal such as a phone supporting the SMS or an intelligent phone supporting the GPRS or the Wi-Fi or an intelligent terminal or a set-top box connected with the broadband network, these terminals can support the information indication in the non-call media channel.
Currently, the ring back tone service is mainly realized in the following ways:
1. Fixed Network Ring Back Tone Realization Solution Based on the PSTN
Generally, the PSTN network can use the called party office to trigger the ring back tone service. The principle is that the called party office records the ring back tone registration information of the user and determines the ring back tone registration information when a call arrives so that when the called party has registered for the ring back tone and the status allows, the call is routed to the ring back tone service platform to be processed and the called party office has the ability to prevent the ring back tone service from being triggered twice. The realization of the fixed network ring back tone based on the PSTN is shown in FIG. 1.
2. Mobile Network Ring Back Tone Realization Solution Based on the GSM
The GSM network also uses the called party office to trigger the ring back tone service. The principle is that the called party office records the ring back tone registration information of the user and determines the ring back tone registration information when a call arrives so that when the called party has registered for the ring back tone and the status allows, the call is routed to the ring back tone service platform to be processed.
Generally the mode without channel alternate is adopted, i.e. the ring back tone service platform plays the subscribed ring back tone according to the call information and the called party bridges the calling party, called party and the ring back tone service platform so that when the called party rings the calling party will hear the ring back tone; after the called party answers the phone, the calling party and the called party begin to communicate and the ring back tone path will be released. The realization of the mobile network ring back tone based on the GSM is shown in FIG. 2.
The characteristics of the GSM mobile network can solve the problem when the user of the ring back tone service roams.
3. Packet Network Multimedia Ring Back Tone Realization Solution Based on the NGN/3G
Generally, the NGN/3G network uses the soft switch office to trigger the ring back tone service. The principle is: the called party office records the ring back tone registration information of the user and determines the ring back tone registration information when a call arrives, so that when the called party has registered for the ring back tone and the status allows, the call is routed to the multimedia ring back tone service platform to be processed. Generally the application server is responsible for the connection and disconnection between the calling party, the called party and the multimedia ring back tone service platform. The realization of the packet network multimedia ring back tone based on the NGN/3G is shown in FIG. 3.